Refrigeration



March 22, 1932. G. AND ESEN' 1,850,907

REFRIGERATION Filed Jul .29, 1929 s Sheets-:Sheet 1 March 22,1932. 3ANDRESEN 1,850,907

' REFRIGERATION Filed July 29, 1929 3 Sheets-Sheet 2 Patented Mar. 22,1932 UNITED v,STATES PATENT OFFICE GEORGE ANDRESEN, OF CHICAGO,ILLINOIS; ASSIGNOR '10 W. B. PABKYN, OI CHICAGO, ILLINOIS REFRIGERATIONApplication filed I111y 29, 1929. Serial No. 881,862.

case of a compressor having intermeshing compressing elements, inadvance of, or substantially at, the point of mesh of such elements) toeffect the discharge, to a reservoir, of the compressed gas and thesealing fluid.

To secure the desired high operating efficiency of the compressor it isdesirable that the pressure in the compressor should be confined to thearea effecting compression and proportionately to the progressiveclosing of the space or the spaces in which the gaseous refrigerant tobe compressed is entrapped.

The compressor serves to compress the gasified refrigerant and deliverit to a condenser from which the refrigerant in liquefied condition issupplied to an evaporator for eflecting the desired refrigeratingaction, the refrigerant passing from the evaporator back to thecompressor forflrecompression, provision being made in the apparatusfor' separating the sealing liquid from the refrigerantdischargedfrom'theucompressor, the sealing liquid thus separated being returned tothe compressor by subjection to ,the head pressure produced by thecompressor. I y

In such apparatus the passage of compressed gaseous refrigerant from theseparator referred to to the condenser is effected by a differential ofpressure between the condenser and the separator, due to the containedheat of friction and compression in the compressed gas discharged intothe separator which latter is removed from cooling influences.

It is characteristic of compressors and especially rotary compressors,that as the differential between the head pressure and the 5 pressure ofthe gaseous refrigerant at the point at which the sealing liquidcontacts with the compressing element increases, the quantity of sealingliquid delivered to the compressor increases and the volumetricdisplacement of gaseous compressed refrigerant decreases.

As the compressed gaseous refrigerant in its passage from the compressorto the condenser extracts heat from the sealing liquid, and as the totalamount of heat extracted therefrom varies in proportion to the sealingliquid and the gaseous refrigerant discharged from the compressor, anincrease in the differential between the head pressure and the pressureof the gaseous refrigerant at the point at which it is contacted by thereturned sealing liquid in the com ressor results in i the return of thesealing liquid to the compressor in a larger volume'and at asubstantially higher temperature, the presence of this heat resulting inthe overheating of the compressor and impairing the proper functioningthereof.

In accordance with methods as hitherto practiced in apparatusas'hitherto provided, the sealing liquid is introduced into thecompressor, throughout the range of the operatingcycle at temperatureseither substan- I tiallyf lower or higher than that of the gasig0 fiedrefrigerant at its point of discharge from the compressor, due tovariations in temperatures of the cooling medium and variations in thecondenser temperatures, with the disadvantages that when the temperatureof the sealing liquid introduced intot'he compressor is lower than thegasified refrigerant discharged from the compressor, objectionable dragdue to the relatively low viscosity of the sealing liquid, results, andthe cooling effect of the sealing liquid on the gas being compressedresults in further lowering the efliciencyof the compressor due to anadded duty being imposed thereon in the raising of the temperature ofthe mixture of the gaseous refrigerant and the noncompressible sealingfluid in the compressor'to the thermal heat required to effect dischargefrom the compressor against the high side pressure.

When the sealing liquid is introduced into the compressor at atemperature substantially higher than the temperature of the refrigerantat the point of discharge from the compressor, the generation ofobjectionable gas-pressure in the compressor, due to the prematureheating of the gaseous refrigerant, results, with the disadvantage ofgencrating high friction in the compressor resulting in objectionablehigh pressure on a large portion of the faces of the compressingelements and consequent objectionable braking effect on said faces,requiring the compressor to operate against the resistance of such highinternal pressure, and subjecting the bearings of the compressor toexcessive stress with con sequent friction and loss in efiiciency due tothe increase of pressure on the faces of the compressing elements overthat of the progressive pressure produced by the progressive compressingaction.

One of my ob] ects is to overcome the ob ections above set forth and toprovide for the introduction of the sealing liquid into the compressorat a temperature substantially that of the compressed gaseousrefrigerant at the point of discharge from the compressor, regardless ofvariations in temperature of the gaseous refrigerant on the high side ofthe apparatus. i

Another object is to accomplish the purpose above stated byapparatuswhich shall operate automatically to cause the temperature of thesealing liquid to rise and fall responsive to the rise and fall ofthetemperature of the gaseous refrigerant at the point of discharge fromthe compressor; and by apparatus which shall be of simple, compact,

and economical construction and operable at the minimum cost.

. Another object is to effectively stabilize the condensing of gaseousrefrigerant and the temperature-conditioning of the sealingliquidthroughoutthe entire range of volumetric displacement of the compressor;and other objects as will be manifest from the follow- Figure 3 is asectional view of the compressor comprising an element of the apparatusshown, the section being taken at the lines 3 on Figs. 1 and 4 andviewed in the direction of the respective arrows.

Figure 4 is a section taken at the line 4 on Fig. 3 and viewed in thedirection of the ar row.

Figure 5 is a section taken at the line 5 on F ig. 3 and viewed in thedirection of the arrow; and

Figure 6, a broken sectional View of the side wall-forming portion ofthe casing of the compressor with the gears omitted, this view beingtaken at the line 5 on Fig. 3 and viewed in the direction of the arrow.

Referring to the particular illustrated construction the apparatuscomprises a compressor 7 which may be, and preferably is, of the wellknown intermeshing herring-bone gear type, the inlet of the compressorcom municating with a pipe 8 and its outlets, lo-

cated at opposite ends of the compressor, with a pipe 9, the compressorbeing shown as driven by an electric motor 10 the armature shaft ofwhich is provided with a fan 11 l0- cated between the motor andcompressor. The pipe 9 leads to a separator device 12 for directing thecompressed gas and entrained sealing liquid into this device whichlatter is provided with a gas outlet pipe 13 which communicates with theupper end of a condenser element 14 shown aslocated in alinement withthe compressor 7 and motor 10, a housing 15, opening at its oppositeends being arranged about the compressor 7 and the condenser 14. Thecondenser discharges at its lower end into a liquid-refrigerant receiver16 which is in the form of a tank located within the housing 15, thetank 16 communicatin at its upper end with a pipe 17.

The refrigerating element of the apparatus is represented generally at18 and is shown as comprising a plurality of yokeshaped pipes 19 whichmay extend into the space to be cooled, or into a bath of circulatingbrine, as is well known in the art. The pipes 19 -open upwa'rdlythroughthe bottom 20 of a float chamber 21 having an inlet 22 in its side wall,valved at 23, and communicating with the pipe 17, the valve 23cooperating with a float-lever 24 and operating to close the chamber 21to the pipe 17 when the level of the liquid refrigerant rises in thischamber toa predetermined point, and to establish communicationbetweenthe pipe 17 and this chamberwhen the level of the liquid thereindrops below such predetermined .point, the refrigerating liquid fillingthe pipeslfi. The

chamber 21 contains a gas outlet 25 shown as opening into this chamberclose to the top thereof and communicating with the pipe 8. v Thearrangement shown and described is thus of the closed circuit type, thegasified refrigerant, which becomes gasified in-the refrigeratingelement 18, in performing the refrigerating function, being sucked intothe compressor 7 from which it is discharged in compressed conditionthrough the pipe 9, the separator 12, and into the condenser 14, inwhich latter it is liquefie'd and collected in the liquid receiver 16,the liquefied refrigerant feeding to the float chamber 21 under thecontrol of the valve 23.

As further description of the construction and operation of the gearcompressor shown, it may be stated that it comprises a casing 26chambered as represented at 27 to receive herringbone gears 28journalled in the casing at shafts 29 thereof one of which shaftsconnects with the armature shaft of themotor 10, the gears 28 rotatingin the direction of the respective arrows in Fig. 3. The passage in thecasing 26 through which the gas pass ing through the pipe 8 to thecompressor discharges into the spaces between the teeth of the gears, isrepresented at 30 and is shown as located midway between the ends of thegears. The gas introduced into the gears, in

the rotation of the latter as stated, is caused by the intermeshing ofthe gears to be compressed and in such condition discharged at the endsof the gears through the outlets 31 in the casing which communicate withthe pipe 9. v

The casing 26 contains an inlet 32 for sealing liquid such as forexample .oilcommon- 1y used for sealing compressors and of particularimport-ancein a compressor of the type shown ,to provide a sealing filmbetween the peripheries of the gears and the casing in which theyrotate, this inlet being shown as located midway between the ends of thegears 26 and so positioned as to communicate with the spaces between thegears at their points of initial intermesh, the passage 32 communicatingwith a pipe 33 opening into the lower portion of the tank 12 and thus incommunication with the body of sealing liqui'd in the latter, thearrangement shown being such that the sealing liquid 1s forced throughthe pipe 33 and into the compressor by reason of the head pressureexerted against the sealing liquid in the tank 12.

In accordance withthe preferred embodi ment of my invention and as Iprefer to practice it, the sealing liquid in its passage from theseparator 12 to the compressor is subjected to thetemperature-controlling action of the liquefied refrigerant as liquefiedin the condenser, it .being preferred that the pipe 33 be formed with acoil section 34 immersed in the body of liquefied refrigerant in thetank 16. I n

The temperature of the sealing liquid flowing to the compressor is thuscaused to besubstantially that of the gaseous refrigerant at the pointof dischar e from the compressor, the temperature of t e sealing liquidrising and falling with the temperatlire of the gaseous refrigerant andthereby the objections above noted in describing the effect of theintroduction of the sealing liquid into the compressor in either. toocold or too heated a condition, are prevented, the compressor thusfunctioning closely in accord with the law of adiabatic heat generation.

It has been found in practice that this stabilization of the heatdissipation generated in the compressor may be effected without 0requiring the use of a condenser of greater capacity than hithertoprovided in apparatus in which the sealing liquid, separated from thecompressed refrigerant, has its temperature controlled otherwise than bythe action of the condenser, it being noted that as the differentialbetween the pressure on the high able to a proportionate degree for thedesired.

temperature conditioning of the increased volume of sealing liquid.

What I claim as new, and desire to secure by Letters Patent is:

1. In refrigerating apparatus the combination of a compressor employinga sealing liquid, a separator for the compressed refrigerant andthesealing liquid delivered by said compressor, a condenser forcondensing the compressed refrigerant, an evaporator in communicationwith said condenser and with the inlet of the compressor, anda conduitthrough which the sealing liquid separated from the refrigerant isreturned to said compressor, said conduit being so disposed that it issubjected to the temperature-controlling effect of the refrigerantcooledby said condenser. t

2. In refrigerating apparatus the combination of a compressor employinga sealing liquid, a separator for the compressed refrigerant and the.sealing liquid delivered by said compressor, a condenser for"condensingthe compressed refri erant, a receptacle for the frigerant receiver; thecombination of a separator for the compressed refrigerant and a sealingliquid delivered by the compressor, and a conduit through which thesealing liquid separated from the refrigerant is returned to saidcompressor, said conduit being so disposed in the body of liquefiedrefrigerant in said liquid receiver as to cause the seal ing liquid tobe subjected to the temperaturecontrolling effect of-the condensedrefrigerant.

GEORGE ANDRESEN.

